java - JSF 2.0 包含 ICEfaces 组件，尝试将 JPA 2.0 用于 JBOSS 独立服务器的 Persistence failed(nullpointException)

Question

我正在尝试编写一个仅使用表单的小型网站。我使用 Eclipse IDE(indigo) 和 JBOSS AS 7.1 服务器。我使用 JSF 2.0 和最新的 ICEfaces 组件进行了编码。现在我已经添加了 JPA 组件来读取/写入 oracle 数据库。实体是为示例表创建的，我能够映射到数据库。但是在运行时，当我尝试从 bean 调用实体管理器以获取持久性单元时，它会得到空值。我不确定我在哪里做错了。

这是实体，持久性文件，bean，xhtml的代码

    package org.icefaces.training.applicant.view.model;

import java.io.Serializable;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;
import javax.faces.event.AjaxBehaviorEvent;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.PersistenceUnit;
import javax.persistence.Query;
import javax.transaction.NotSupportedException;
import javax.transaction.SystemException;
import javax.transaction.UserTransaction;

import org.icefaces.training.applicant.model.EmployeesEntity;

@ManagedBean(name = "jobApplicant")
@ViewScoped
public class JobApplicant implements Serializable {
    private String firstName;
    private String lastName;
    private String country;
    private String title;
    private Integer salary;
    private String email;
    private String subject;
    private String resume;
    private String lastName1;

    @PersistenceUnit(unitName="jobApplication")
    private EntityManagerFactory emf;





    public String getValue() throws NotSupportedException, SystemException
    {
    EntityManagerFactory emf = Persistence.createEntityManagerFactory("jobApplication");
        EntityManager em = emf.createEntityManager();
        EmployeesEntity emp = em.find(EmployeesEntity.class, 207);

        return emp.getLAST_NAME();

    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public String getResume() {
        return resume;
    }

    public void setResume(String resume) {
        this.resume = resume;
    }

    public  void submit(ActionEvent ae) {
    if (firstName.equals("joe") && lastName.equals("bush")){
        String str="Joe Bush is already existed";
        FacesMessage facesMessage = new FacesMessage(str);
        FacesContext facesContext = FacesContext.getCurrentInstance();
        String clientID = null; // this is a global message
        facesContext.addMessage(clientID, facesMessage);
    }
    }

    @Override
    public String toString() {
        return "jobApplicant " + super.toString();
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Integer getSalary() {
        return salary;
    }

    public void setSalary(Integer salary) {
        this.salary = salary;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
    @PostConstruct
    public void clear() {
        setFirstName("");
        setLastName("");
        setCountry("");
        setSalary(0);
        setEmail("");
        setTitle(null);
    }




}

实体

package org.icefaces.training.applicant.model;

import java.io.Serializable;
import java.lang.Number;
import java.lang.String;
import javax.persistence.*;
import static javax.persistence.AccessType.FIELD;

/**
 * Entity implementation class for Entity: EmployeesEntity
 *
 */
@Entity

@Table(schema = "TUHRA", name = "EMPLOYEES")

public class EmployeesEntity implements Serializable {

    @Id
    private Number Employee_ID;
    private String FIRST_NAME;
    private String LAST_NAME;
    private static final long serialVersionUID = 1L;

    public EmployeesEntity() {
        super();
    }   
    public Number getEmployee_ID() {
        return this.Employee_ID;
    }

    public void setEmployee_ID(Number Employee_ID) {
        this.Employee_ID = Employee_ID;
    }   
    public String getFIRST_NAME() {
        return this.FIRST_NAME;
    }

    public void setFIRST_NAME(String FIRST_NAME) {
        this.FIRST_NAME = FIRST_NAME;
    }   
    public String getLAST_NAME() {
        return this.LAST_NAME;
    }

    public void setLAST_NAME(String LAST_NAME) {
        this.LAST_NAME = LAST_NAME;
    }

}

持久性.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="jobApplication">

    <provider>org.hibernate.ejb.HibernatePersistence</provider> 
    <!--   <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> -->
     <jta-data-source>java:/OracleJINDI</jta-data-source>
    <class>org.icefaces.training.applicant.model.EmployeesEntity</class>
      <properties>
      <!-- <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver" />
      <property name="hibernate.connection.url" value="jdbc:oracle:thin:@oracleapps:1521:PROD" />
      <property name="hibernate.connection.username" value="tuhra" />
      <property name="hibernate.connection.password" value="tuhra" /> -->


      </properties>

    </persistence-unit>
</persistence>

xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://java.sun.com/jsf/facelets"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:f="http://java.sun.com/jsf/core"
      xmlns:icecore="http://www.icefaces.org/icefaces/core"   xmlns:ace="http://www.icefaces.org/icefaces/components"    xmlns:ice="http://www.icesoft.com/icefaces/component">

<h:head>


    </h:head>
    <h:body >
    <ui:composition template="/WEB-INF/templates/template.xhtml" >
    <ui:param name="title" value="Applicant System" />
    <ui:define name="header">
    <h:graphicImage library="images" name="icefaces.png" />
    <h:outputStylesheet library="css" name="jobApplication.css" /> 
    </ui:define>
    <ui:define name="menu">
    <h:button outcome="applicants" value="Listing Page" />
    </ui:define>
    <ui:define name="content">

    <h:messages globalOnly="true" />
    <h:form>
    <h:panelGrid columns="3">
    <h:outputLabel for="title" value="Title: " />
    <h:selectOneRadio id="title" value="#{jobApplicant.title}"  required="true">
     <f:selectItem itemLabel="Dr." itemValue="1"/>
      <f:selectItem itemLabel="Ms." itemValue="2"/>
       <f:selectItem itemLabel="Mrs." itemValue="3"/>
        <f:selectItem itemLabel="Miss." itemValue="4"/>
         <f:selectItem itemLabel="Mr." itemValue="5"/>
     </h:selectOneRadio>
     <h:message for="title" />
        <h:outputLabel for="firstName" value="First Name"></h:outputLabel>
        <h:inputText id="firstName" value="#{jobApplicant.firstName}" required="true" 
        converter="wordCapitalization"/>
        <h:message for="firstName" />
        <h:outputLabel for="lastName" value="Last Name"></h:outputLabel>
        <h:inputText id="lastName" value="#{jobApplicant.lastName}" required="true"
        converter="wordCapitalization" />
        <h:message for="lastName" />
        <h:outputLabel for="country" value="Country" />
        <h:selectOneMenu id="country" value="#{jobApplicant.country}" required="true">
         <f:selectItem itemLabel="-Select-" noSelectionOption="true"/>
         <f:selectItems value="#{countryList.countries}"/>
        </h:selectOneMenu> 
        <h:message for="country" />
        <h:outputLabel for="salary" value="Salary: " />
        <h:inputText id="salary" value="#{jobApplicant.salary}" required="true">
    <f:validateLongRange minimum="1" maximum="1000000"/> 
        <f:convertNumber type="currency"   />
        </h:inputText>
        <h:message for="salary" />
        <h:outputLabel for="email" value="Email: " />
        <h:inputText id="email" value="#{jobApplicant.email}"  validator="emailValidator" required="true"/>
        <h:message for="email"/>
        <h:outputLabel for="lastname1" value="Last Name: " />
        <h:outputText value="#{jobApplicant.value}" />
        <h:message for="lastname1"/>


        <h:outputLabel for="subject" value="Subject: " />
                    <ice:inputText id="subject" value="#{jobApplicant.subject}"></ice:inputText>
                    <h:message for="subject"/>
        <h:outputLabel for="body" value="Body: " />
                    <ice:inputRichText id="resume" saveOnSubmit="true" toolbar="Default" width="500" height="200" value="#{jobApplicant.resume}"></ice:inputRichText>
                    <h:message for="body"/>
                    <h:commandButton value="Submit: Applicant" action="#{applicationController.addApplicant}" />

         <h:commandButton id="clearButton" value="Clear" >
         <f:ajax event="click" render="@form" listener="#{applicationController.clearForm}" immediate="true"/>
         </h:commandButton>
         <h:commandButton id="cancelButton" action="cancelJobApplication" immediate="true" value="Cancel" />
      </h:panelGrid>
    </h:form>
    </ui:define>
    <ui:define name="footer">
    <br />
    - Server - <br />
    Title: <h:outputText value="#{jobApplicant.title}" /> <br />
    First Name: <h:outputText value="#{jobApplicant.firstName}" /> <br />
    Last Name: <h:outputText value="#{jobApplicant.lastName}" /> <br />
    Country: <h:outputText value="#{jobApplicant.country}" /><br />
    Salary: <h:outputLabel value="#{jobApplicant.salary}" /><br />
    Email: <h:outputLabel value="#{jobApplicant.email}" /><br />
    Applicants: <h:outputLabel value="#{applicants.applicantsList}" /><br />
    </ui:define>
    </ui:composition>
</h:body>
</html>

---

感谢您的回复，但是当我浏览以下书籍时，我认为是正确的。

    @PersistenceUnit(unitName="jobApplication")
private EntityManagerFactory emf;
public String getValue() throws NotSupportedException, SystemException {
EntityManager em = emf.createEntityManager();
 EmployeesEntity emp = em.find(EmployeesEntity.class, 207);
        return emp.getLAST_NAME();
}

但我仍然收到错误，这可能是由于从 JBOSS 7.1 运行时库中使用的 JPA2.0 [休眠]。以下是我得到的错误，我错过了什么

13:34:08,316 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (http--127.0.0.1-8080-1) Error Rendering View[/job-applicant.xhtml]: java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:163) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.ee.component.BasicComponent.createInstance(BasicComponent.java:95) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.web.deployment.component.WebComponentInstantiator$2.<init>(WebComponentInstantiator.java:96) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.web.deployment.component.WebComponentInstantiator.initializeInstance(WebComponentInstantiator.java:94) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.web.deployment.WebInjectionContainer.newInstance(WebInjectionContainer.java:86) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.web.deployment.jsf.JsfInjectionProvider.invokePostConstruct(JsfInjectionProvider.java:69) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
    at com.sun.faces.mgbean.BeanBuilder.invokePostConstruct(BeanBuilder.java:223) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:105) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:72) [jbossweb-7.0.10.Final.jar:]
    at org.apache.el.parser.AstValue.getValue(AstValue.java:147) [jbossweb-7.0.10.Final.jar:]
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189) [jbossweb-7.0.10.Final.jar:]
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.UIOutput.getValue(UIOutput.java:169) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at com.sun.faces.renderkit.html_basic.MenuRenderer.getCurrentSelectedValues(MenuRenderer.java:648) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.renderkit.html_basic.SelectManyCheckboxListRenderer.encodeEnd(SelectManyCheckboxListRenderer.java:122) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:312) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at org.icefaces.impl.renderkit.RendererWrapper.encodeChildren(RendererWrapper.java:49) [icefaces.jar:]
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.10.Final.jar:]
    at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:154) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.10.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.10.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.10.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.10.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.10.Final.jar:]
    at java.lang.Thread.run(Unknown Source) [rt.jar:1.6.0_25]
Caused by: javax.persistence.PersistenceException: Hibernate cannot unwrap interface javax.persistence.EntityManagerFactory
    at org.hibernate.ejb.AbstractEntityManagerImpl.unwrap(AbstractEntityManagerImpl.java:1173) [hibernate-entitymanager-4.0.1.Final.jar:4.0.1.Final]
    at org.jboss.as.jpa.container.AbstractEntityManager.unwrap(AbstractEntityManager.java:68) [jboss-as-jpa-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.jpa.injectors.PersistenceContextInjectionSource$PersistenceContextJndiInjectable.getReference(PersistenceContextInjectionSource.java:188) [jboss-as-jpa-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.as.ee.component.ManagedReferenceFieldInjectionInterceptorFactory$ManagedReferenceFieldInjectionInterceptor.processInvocation(ManagedReferenceFieldInjectionInterceptorFactory.java:104) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.as.ee.component.ManagedReferenceInterceptorFactory$ManagedReferenceInterceptor.processInvocation(ManagedReferenceInterceptorFactory.java:106) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:161) [jboss-as-ee-7.1.0.Final.jar:7.1.0.Final]
    ... 54 more

Answer 1

代替

@PersistenceUnit(unitName="jobApplication")
private EntityManagerFactory emf;

public String getValue() throws NotSupportedException, SystemException {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("jobApplication");
        EntityManager em = emf.createEntityManager();
        EmployeesEntity emp = em.find(EmployeesEntity.class, 207);

        return emp.getLAST_NAME();
}

你能试试：

@PersistenceContext
private EntityManager em;

public String getValue() throws NotSupportedException, SystemException {
        EmployeesEntity emp = em.find(EmployeesEntity.class, 207);

        return emp.getLAST_NAME();
}

我不知道这是否有帮助，但这样代码更干净:)